1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to an apparatus for transmitting and receiving signals in a multi-node system using a sum rate analysis and method thereof.
2. Discussion of the Related Art
Recently, a data traffic for a network within a wireless communication system is increasing rapidly in a wireless communication environment due to the advent and spread of various kinds of high data traffic requiring devices such as M2M devices having M2M (machine-to-machine) communications applied thereto, smart phones, tablet computers and the like. In order to meet such a massive data traffic, communication technologies are being developed into such a category to efficiently use more frequency bands as carrier aggregation technology, cognitive radio technology and the like and such a category to increase data capacity within a limited frequency as multi-antenna technology, multi-base station coordination technology and the like. And, a wireless communication environment is being evolved in a direction to increase density of nodes accessible around users. In particular, such a system equipped with high node density may provide enhanced system performance owing to inter-node coordination. This system may perform cooperative communications using a plurality of nodes each of which plays a role as a base station (e.g., advanced BS, Node-B, eNode-B, AP (access point), antenna, antenna group, RRH (radio remote header), RRH (radio remote unit), etc.).
As transmissions and receptions of all nodes are controlled by a single controller, if an individual node works as a partial antenna group of one base station, this system may be regarded as one DNS (distributed antenna system). In particular, a separate Node ID may be given to each individual node or may work as a partial antenna within a cell without a separate Node ID.
Meanwhile, if each node in DNS perform scheduling and handover with a different cell ID, it may be regarded as a multi-cell (e.g., macro cell, femto cell, pico cell, etc.) system. In case that multiple cells respectively formed by a plurality of nodes are configured in a manner of being overlaid in accordance with coverage, this may be named multi-tier network.
Meanwhile, base stations of various types may be used as nodes irrespective of their names, respectively. In particular, any one of BS (Base Station), NB (Node-B), eNB (eNode-B), pico-cell eNB (PeNB), Home eNB (HeNB), RRH, RRH, relay, repeater and the like may become a node. At least one antenna is installed at one node. In this case, an antenna may mean a physical antenna or one of an antenna port, a virtual antenna and an antenna group. And, a node may be called a point.
A node may normally indicate an antenna group spaced apart over a predetermined interval. And, a node may be applicable in case of meaning a random antenna group irrespective of interval. For instance, a base station may be defined to control a node consisting of H-pol antenna and a node consisting of V-pol antenna.